Never mind all those maps of red and blue America, a nation polarized between Democrat and Republican, city and country, with entire elections teetering on the last-minute decisions of a few Ohio soccer moms. Forget what you know about the inaccessible general-election candidate, hidden behind layers of Secret Service and stage-managed pomp. Scratch those notions of a Republican Party that sidles up to pharmaceutical companies and oil giants, never ruffling the paymasters' feathers.
With much of the attention focused on the unprecedented photo finish of a woman and an African American in the Democratic primaries, it's easy to underestimate how much...